The 2012 winners play Schalke, who have maximum points from two matches, at the Veltins Arena in Gelsenkirchen on Tuesday night in their first return to Germany since lifting the European Cup in Munich.
Speaking at Dusseldorf Airport on the Blues' arrival in Germany, Mourinho said: "I don't think it's yet the time to have the calculator and to be counting the number of points you need to qualify, or to be first or second, or to go into the Europa League (as third-placed side).
"The calculator comes on the fifth fixture. The third and the fourth are still fixtures we can play just thinking about the game and trying to win, and if you cannot win try to get a point.
"We lost the first match at home (2-1, to Basle) but won the second away (4-0, at Steaua Bucharest), so we found a balance.
"We play two matches against the strongest opponent in the group, which leaves us the fifth and sixth fixture to play against Basle and Steaua.
"We need points over these two matches (against Schalke). That's obvious. But we're in condition to play without thinking about finishing first or second."
Chelsea and Schalke last met in November 2007 in the Champions League group stages, soon after the end of Mourinho's first spell as boss.
The Blues reached the final in Moscow in May 2008, losing on penalties to Manchester United, before winning the tournament four years' later against Bayern Munich.
Last season, Chelsea suffered the ignominy of becoming the first holders to exit the competition at the group stage and responded by winning the Europa League, a tournament Mourinho has no interest in.
To take control of Group E, Chelsea must beat a Schalke side who have won eight of their last 10 games, losing once, to European champions Bayern.
But Schalke have a mixed recent record against English clubs in European competition.
They beat Arsenal at the Emirates Stadium 12 months ago, but lost heavily to Manchester United in the Champions League semi-finals in May 2011.
Mourinho's appraisal was simple.
"A good team, a good opponent," he said. "Hopefully we can be better than them."
Chelsea must do without Ashley Cole (ribs), who is absent, perhaps with Sunday's Barclays Premier League match with Manchester City in mind.
Andre Schurrle, who scored four times in two games for Germany earlier this month, did travel and has impressed his manager since arriving from Bayer Leverkusen.
"He's a good player, he's an open kid," Mourinho said.
"He wants to work, he wants to learn, so our hopes on him and the money we've invested on him, we're happy with that investment.
"Such a young player, we believe he will be better and better."
Schurrle could be thrust straight into the side, but David Luiz could make way after a number of errors in Saturday's defeat of Cardiff.
Gary Cahill could come in for Luiz and partner John Terry at centre back.
"Normally the players who are here (at the pre-match media conference) are playing, so I have to make a choice between David and Gary. A choice that I did already."
Terry had earlier been sitting alongside Mourinho.
The Chelsea captain knows Schalke will be a challenge.
He said: "We're not coming here under false pretences that we're going to come here pick up three points easily. We understand it's going to be a tough night.
"We had a minor blip at home (against Basle). Win this game tomorrow and we're in a much stronger position."